Why is baking powder important to a recipe?

If baking powder is called for in a recipe, it is essential. The base and acid components in the powder, when wet, create the air bubbles that cause the dough to rise, making the end product soft and allowing it to cook thoroughly. Without the baking powder or baking soda (see below), the result of baking unleavened dough will be just hot dough or perhaps dough dried hard. If you have no baking powder but have baking soda, you can substitute a combination of baking soda plus an acidic ingredient, such as molasses, buttermilk or yogurt, or even a little citrus juice.